ImageRenderer is one other new API for SwiftUI that comes with iOS 16. It lets you simply convert any SwiftUI views into a picture. The implementation could be very easy. You instantiate an occasion of ImageRenderer with a view for the conversion:
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let renderer = ImageRenderer(content material: theView) |
You may then entry the cgImage or uiImage property to retrieve the generated picture.
As all the time, I like to reveal the utilization of an API with an instance. Earlier, we’ve constructed a line chart utilizing the brand new Charts framework. Let’s see how you can let customers save the chart as a picture within the photograph album and share it utilizing ShareLink.
Revisit the Chart View
First, let’s revisit the code of the ChartView instance. We used the brand new API of the Charts framework to create a line chart and show the climate knowledge. Right here is the code snippet:
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var physique: some View {     VStack {         Chart {             ForEach(chartData, id: .metropolis) { collection in                 ForEach(collection.knowledge) { merchandise in                     LineMark(                         x: .worth(“Month”, merchandise.date),                         y: .worth(“Temp”, merchandise.temperature)                     )                 }                 .foregroundStyle(by: .worth(“Metropolis”, collection.metropolis))                 .image(by: .worth(“Metropolis”, collection.metropolis))             }         }         .chartXAxis {             AxisMarks(values: .stride(by: .month)) { worth in                 AxisGridLine()                 AxisValueLabel(format: .dateTime.month(.defaultDigits))              }         }         .chartPlotStyle { plotArea in             plotArea                 .background(.blue.opacity(0.1))         }         .chartYAxis {             AxisMarks(place: .main)         }         .body(width: 350, top: 300)         .padding(.horizontal)      } } |
To make use of ImageRenderer, we first refactor this piece of code right into a separate view like this:
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struct ChartView: View {     let chartData = [ (city: “Hong Kong”, data: hkWeatherData),                       (city: “London”, data: londonWeatherData),                       (city: “Taipei”, data: taipeiWeatherData)     ]         var physique: some View {         VStack {                         Chart {                 ForEach(chartData, id: .metropolis) { collection in                     ForEach(collection.knowledge) { merchandise in                         LineMark(                             x: .worth(“Month”, merchandise.date),                             y: .worth(“Temp”, merchandise.temperature)                         )                     }                     .foregroundStyle(by: .worth(“Metropolis”, collection.metropolis))                     .image(by: .worth(“Metropolis”, collection.metropolis))                 }             }             .chartXAxis {                 AxisMarks(values: .stride(by: .month)) { worth in                     AxisGridLine()                     AxisValueLabel(format: .dateTime.month(.defaultDigits))                                     }              }             .chartPlotStyle { plotArea in                 plotArea                     .background(.blue.opacity(0.1))             }             .chartYAxis {                 AxisMarks(place: .main)             }             .body(width: 350, top: 300)             .padding(.horizontal)                     }     } }  |
Subsequent, we declare a variable to carry the view:
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var chartView = ChartView() |
Changing the View into an Picture utilizing ImageRenderer
Now we’re able to convert the chart view into a picture. We are going to add a button named Save to Photographs for saving the chart view picture within the photograph album.
Let’s implement the button like this:
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var physique: some View {      VStack(spacing: 20) {         chartView          HStack {             Button {                 let renderer = ImageRenderer(content material: chartView)                  if let picture = renderer.uiImage {                     UIImageWriteToSavedPhotosAlbum(picture, nil, nil, nil)                 }             } label: {                 Label(“Save to Photographs”, systemImage: “photograph”)             }             .buttonStyle(.borderedProminent)         }     }  } |
Within the closure of the button, we create an occasion of ImageRenderer with chartView and get the rendered picture through the use of the uiImage property. Then we name UIImageWriteToSavedPhotosAlbum to avoid wasting the picture to the photograph album.
Word: It’s essential add a key named Privateness – Picture Library Utilization Description within the information.plist earlier than the app can correctly save a picture to the built-in photograph album.
Including a Share Button
Earlier, you discovered how you can use ShareLink to current a share sheet for content material sharing. With ImageRenderer, you possibly can simply construct a perform for customers to share the chart view.
For comfort goal, let’s refactor the code for picture rendering right into a separate methodology:
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@MainActor non-public func generateSnapshot() –> UIImage { Â Â Â Â let renderer = ImageRenderer(content material: chartView) Â Â Â Â Â return renderer.uiImage ?? UIImage() } |
The generateSnapshot methodology converts the chartView into a picture.
Word: In case you are new to @MainActor, you possibly can try this text.
With this helper methodology, we will create a ShareLink like this within the VStack view:
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ShareLink(merchandise: Picture(uiImage: generateSnapshot()), preview: SharePreview(“Climate Chart”, picture: Picture(uiImage: generateSnapshot()))) .buttonStyle(.borderedProminent) |
Now whenever you faucet the Share button, the app captures the road chart and allows you to share it as a picture.
Adjusting the Picture Scale
It’s possible you’ll discover the decision of the rendered picture is a bit low. The ImageRenderer class has a property named scale so that you can alter the size of the rendered picture. By default, its worth is ready to 1.0. To generate a picture with a better decision, you possibly can set it to 2.0 or 3.0. Alternatively, you possibly can set the worth to the size of the display screen:
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renderer.scale = UIScreen.most important.scale |
Abstract
The ImageRenderer class has made it very straightforward to transform any SwiftUI views into a picture. In case your app helps iOS 16 or up, you should use this new API to create some handy options in your customers. Apart from rendering pictures, ImageRenderer additionally helps you to render a PDF doc. You may consult with the official documentation for additional particulars.
For charts, Apple additionally comes with a extra particular renderer known as ChartRenderer for exporting a chart as a picture. Later, we’ll additional look into this class.
Founding father of AppCoda. Writer of a number of iOS programming books together with Starting iOS Programming with Swift and Mastering SwiftUI. iOS App Developer and Blogger. Comply with me at Fb, Twitter and Google+.